Stains are often applied to porous substrates, such as wood, to, for example, provide coloring while allowing some of the substrate's natural color and grain to show through. Historically, there have been two basic types of wood stains: water-based and oil-based.
Water-based stains have been favored from an environmental standpoint, since such compositions contain little or no volatile organic materials that are released into the atmosphere. Such stains, however, have drawbacks. Water-based stains are notorious for causing wood grain-raising. In other words, the water in the stain composition lifts the wood fibers, thereby roughening the wood surface, which often necessitates an additional sanding operation to generate a smooth surface. Also, because they are fast-drying, water-based stains can be difficult to employ as a wiping stain while still obtaining color consistency.
Oil-based stains have also been used and are capable of performing adequately in many cases. They are typically non-grain raising and not quick to dry, i.e., they have a long open time. Such stains, however, have historically required the use of significant amounts of volatile organic material, 250 or more grams of volatile organic material per liter of the stain composition, in order to reduce the viscosity of the composition and/or render the stain dryable. The use of significant amounts of volatile organic materials though, as indicated above, is disfavored from an environmental standpoint.
As a result, it would be desirable to provide stain compositions, such as wiping stains, that are dryable, non grain-raising, have long open time, and which contain little or no volatile organic materials.